This particular invention is directed generally to lighting fixtures and, more particularly, to electronic strobe units for photographic purposes.
Use of electronic strobe units primarily for photographic apparatus is well known. Typically, such strobe units comprise a housing assembly including a parabolic reflector and an electrically energizable flash tube generally surrounded by the reflector. Examples of strobe units and related lighting fixtures are exemplified by the following patents issued to: Elliot, U.S. Pat. No. 3,167,256; Wilde, U.S. Pat. No. 3,167,258; Lones, U.S. Pat. No. 4,135,228; Andra, Canadian Pat. No. 988,063; and to Schmidt, U.S. Pat. No. 3,484,597. One known unit has been manufactured by the Rollei Manufacturing Company of West Germany. This electronic strobe includes a multi-component reflector in a housing with a gas discharge tube projecting through and beyond openings in opposite ends of the reflector and housing. A pair of resilient members secure projecting tube ends to protruding housing ears.
To insure quality photographs when using strobes of the above type, it will be appreciated its output values and light distribution pattern be repeatably consistent with the values and pattern they were calibrated for. Otherwise, the strobes would not perform in the manner intended. Correspondingly, the quality of the resultant photographs would, of course, suffer. Therefore, it is critical for good photographic results to have the strobe perform in the manner intended.
Towards this end, it is highly critical that the flash tube be relatively precisely located relative to the reflector and, in turn, of course, the reflector be relatively precisely located in the housing. It has been determined that if the flash tube is misaligned by as little as a few thousands of an inch, the resulting light distribution pattern will be skewed. As a result, the strobe does not provide the uniform reflectivity desired for insuring uniform brightness characteristics of the photograph. Likewise, reflector misalignments cause similar problems. Moreover, the problems of avoiding inaccurate placement of the flash tube and reflector components are, as noted above, further compounded by the requirement that these difficult to center components as well as the associated housing be of a construction which facilitates manual mass production assembly in an easy, accurate and economical manner. For instance, the noted Rollei strobe unit was determined to have significant drawbacks because of misalignment potential. In this regard, the reflector suffered from the shortcoming of floating (i.e., it was angularly shiftable relative to a preselected position within the housing). Also, a likelihood existed that the separate end reflecting pieces of the multi-component reflector might be installed with their reflecting surfaces not facing each other. Moreover, the flash tube was spaced from the reflector by grommets. Because of this spacing there was a tendency for dust particles to become carburized during flash triggering as a result of the potential existing between the tube and the reflector. These foregoing factors coupled with the absence of means for positively ensuring correct longitudinal positioning of the tube relative to the reflector resulted in a strobe construction having a relatively high probability of component misalignment and was less than entirely successful. As a result, intended light distribution values and patterns were difficult to attain.